G54B / 4G54 2.6 Engine Specs, Problems, Reliability

The 2.6-liter Mitsubishi 4G54 or G54B gasoline engine was produced from 1978 to 1992 and was installed on the Pajero SUV, L200 pickup truck and a number of Chrysler cars. After the end of production in Japan, the engine was assembled by Chinese companies for quite some time.

4G54 / G54B Engine Specs

The weight of the 4G54 / G54B engine according to the catalog is 200 kg

Read Also: 4M40 2.8 Mitsubishi Engine Specs, Problems, Reliability

4G54 / G54B Engine Performance Summary

Here, we will investigate the characteristics of this engine by referring to the data of the G54B type turbo engine installed in Mitsubishi’s A187A type stallion GSR-VR 1988/04 model.

Mitsubishi’s A187A type Stallion GSR-VR
Vehicle model	E-A187A
Car name & grade	Stallion GSR-VR
Engine model	G54B
type	In-line 4-cylinder
Displacement	2555cc
Inner diameter × stroke	91.1mm×98.0mm
Bore stroke ratio	1.08
Single cylinder volume	638.8cc
Compression ratio	7.0
Intake method	turbo
use fuel	High octane gasoline
Maximum output	175PS/5000rpm
Maximum torque	32.0kgm/3000rpm

First of all, as a basic structure, the G54B type engine is a long stroke type engine with a bore (inner diameter) of 91.1 mm, a stroke (stroke) of 98.0 mm, and a bore stroke ratio of 1.08 (the stroke amount is larger than the piston diameter).

When the displacement and the number of cylinders are the same, the engine has better torque characteristics in the low rpm range than the short stroke type and is easy to handle, but in the high rpm range, the filling efficiency deteriorates and the sliding resistance increases. There is a concern that the output will drop.

Moreover, when the number of revolutions is the same, the average piston speed tends to be higher than that of the short stroke type, so the load on the engine tends to be heavier.

The car model equipped with the G54B type turbo engine on this site is the first stallion [A187A type | 1988/04] released in 1982, 0 car models for NA cars, and 2 car models for turbo / SC cars. All 2 models of are registered.

Evaluation from the viewpoint of transient characteristics and liter equivalent horsepower

Image of engine performance curve
Changes in horsepower	134.0PS → 175PS
Transition of torque	32.0kgm → 25.1kgm
Liter horsepower	68.49PS/L
Liter torque	12.5kgm/L

The stallion’s in-line 4-cylinder 2555cc turbo engine with a compression ratio of 7.0 and high-octane gasoline specifications, which is the reference vehicle this time, produces a maximum output of 175 horsepower at 5000 rpm and a maximum torque of 32.0 kgm at 5000 rpm.

If you know the horsepower and the number of revolutions, you can know the torque, and if you know the torque and the number of revolutions, you can know the horsepower. The torque at 5000 rpm is 25.1kgm.

The horsepower per liter of displacement is 68.49PS / L and the torque is 12.5kgm / L, and the horsepower per cylinder (single cylinder volume 638.8cc) is 43.8PS and the torque is 8.0kgm.

When the G54B turbo engine is applied to a 10-step evaluation based on deviation values ​​aggregated from all turbo cars registered on this site, the evaluation is ” modest ” with a converted horsepower of [ 3 ] and a converted torque of [ 4 ]. It is categorized as ” engine of output “.

Displacement increase, compression ratio increase, bore stroke ratio change

There are three factors that determine the engine displacement: the number of cylinders, the bore diameter, and the stroke amount. By increasing or decreasing these, engines with various displacements are created.

Here, regardless of whether it is actually possible, the displacement when the piston diameter is expanded from the genuine 91.1 mm to 94.1 mm in 0.5 mm increments and when the stroke is extended from the genuine 98.0 mm to 103.0 mm in 1 mm increments. And, the change of the compression ratio when it is assumed that the volume of the combustion chamber does not change is listed.

* It is easy to say stroke up, but if you want to make a long stroke, you need a crankshaft and a compatible connecting rod, and if you can not divert it, you have to make it in one-off, so it is expensive anyway. It is a menu that requires considerable preparedness to put out.

Regarding the compression ratio, in most cases, the uneven capacity of the top surface of the piston changes as the diameter of the piston increases, so the compression ratio values ​​in the list do not match, but the displacement. Please enjoy the atmosphere that the compression ratio will naturally increase as you increase the size.

B / S ratio is an abbreviation for bore stroke ratio, and as the bore diameter is widened, the characteristics of the long stroke type, square type, or short stroke type are approached. In the case of G54B type engine, the ratio changes from 1.08 to 1.04 when the bore is increased by +3.0mm from the genuine piston.

Increased displacement with engines with similar piston diameters

There are 8 engines with pistons that are close in size to the G54B type engine with a piston diameter of 91.1 mm, so as a side note, let’s calculate the displacement when the piston is diverted and the bore is raised.

Engines with similar piston diameters are Subaru: EJ20 type 1994cc 92.0mm mounted on VAB type WRX STI, Toyota: 2L type 2446cc 92.0mm mounted on LX80 type Hilux Surf, Toyota: GDJ150W type Land Cruiser Prado 1GD type 2754cc 92.0mm, Daihatsu: DL type 2765cc 92.0mm mounted on F73W type rugger, Subaru: EA82 type 1781cc 92.0mm mounted on AX7 type Alcione, Nissan: Mounted on HF50 type seamer VQ30 type 2987cc 93.0mm etc. are applicable.

(Although the number of people who find pleasure in such a quest has decreased) No matter how close the diameter is, there are factors such as the diameter of the piston pin, the height of the piston, and the convenience of valve recess, so if possible, the same manufacturer, If possible, if you choose the same fuel and the same intake method, and if possible, the one with a similar displacement, the possibility of genuine diversion may increase.

Average piston speed

Next, let’s look at the average piston speed. The average piston speed at 5000 rpm, where an engine with a stroke of 98.0 mm produces maximum output, is 16.3 m / s , which is a piston speed that travels a distance of 16.3 meters per second (58.7 km / h at speed). It means that is moving up and down.

The average speed is 9.8 m / s at 3000 rpm, which produces the maximum torque, and 18.0 m / s when the rev limit is assumed to be 5500 rpm, which is 500 rpm higher than the 5000 rpm where the maximum output is generated.

For reference, I calculated the change in piston speed when a G54B engine with a stroke of 98.0 mm is rotated up to 10000 rpm. Looking at this, it seems that the speed increases by approximately 6.55 m / s as the number of revolutions increases by 2000 revolutions.

Considering only 20.0 m / s, which is a guideline for a general engine assuming mass production, it is mechanical to set the upper limit of high rpm to about 6120 rpm (whether it rotates or not). It seems to be preferred both mentally.

Mitsubishi 4G54 / G54B Engines Used in What Vehicles?

4G54 / G54B Fuel Consumption

On the example of a 1985 Mitsubishi Pajero with a manual transmission:

4G54 / G54B Disadvantages, Breakdowns And Problems

1. This engine belongs to the category of millionaires and has an impressive resource
2. However, due to its rarity, you will certainly have problems with service and spare parts
3. Many modifications are equipped with a Mikuni carburetor that needs to be serviced
4. On a run of more than 200 – 250 thousand km, it may require the intervention of a timing chain
5. Most versions do not have hydraulic lifters and clearances will have to be adjusted

Conclusion

The 4G54 / G54B engine is commonly used in car brands coming off the assembly line in the EU. It has increased potency and almost no irreversible problems in operation. You just need to change the oil and air filter on time. If you need to select spare parts for the G54B engine, use the engine consumables selection guide, carefully check the specifications.